Can't boot into ubuntu on my pc

raxtt · February 23, 2026, 11:23pm

Ubuntu Support Template

Ubuntu Version:
Ubuntu 24.04.3 LTS

Desktop Environment (if applicable)

GNOME(if I remeber correctly)

Problem Description:
After an update, I can no longer boot into Ubuntu.

sudo dmesg | tail -20

What I’ve Tried:
At first, I was getting stuck in the GRUB Menu without being able to make any inputs.

Then, when I changed the monitor, I was able to select Ubuntu to start, and it would give me an error Unable to mount root fs on unknown-block(0,0).

After this, I booted off a USB and ran the boot repair tool.

Now, when I boot up, it goes to the GRUB rescue screen, and I can’t get off of that

Forgot to mention, I have checked to see if secure boot was enabled in my bios, and it wasn’t

Relevant System Information:
https://paste.ubuntu.com/p/QHpzZX63qb/

results for fdisk -l

Disk /dev/loop0: 1.68 GiB, 1805725696 bytes, 3526808 sectors

Units: sectors of 1 * 512 = 512 bytes

Sector size (logical/physical): 512 bytes / 512 bytes

I/O size (minimum/optimal): 512 bytes / 512 bytes

Disk /dev/loop1: 536.45 MiB, 562503680 bytes, 1098640 sectors

Units: sectors of 1 * 512 = 512 bytes

Sector size (logical/physical): 512 bytes / 512 bytes

I/O size (minimum/optimal): 512 bytes / 512 bytes

Disk /dev/loop2: 945.99 MiB, 991940608 bytes, 1937384 sectors

Units: sectors of 1 * 512 = 512 bytes

Sector size (logical/physical): 512 bytes / 512 bytes

I/O size (minimum/optimal): 512 bytes / 512 bytes

Disk /dev/loop3: 4 KiB, 4096 bytes, 8 sectors

Units: sectors of 1 * 512 = 512 bytes

Sector size (logical/physical): 512 bytes / 512 bytes

I/O size (minimum/optimal): 512 bytes / 512 bytes

Disk /dev/loop4: 73.96 MiB, 77549568 bytes, 151464 sectors

Units: sectors of 1 * 512 = 512 bytes

Sector size (logical/physical): 512 bytes / 512 bytes

I/O size (minimum/optimal): 512 bytes / 512 bytes

Disk /dev/loop5: 251.67 MiB, 263892992 bytes, 515416 sectors

Units: sectors of 1 * 512 = 512 bytes

Sector size (logical/physical): 512 bytes / 512 bytes

I/O size (minimum/optimal): 512 bytes / 512 bytes

Disk /dev/loop6: 226.61 MiB, 237617152 bytes, 464096 sectors

Units: sectors of 1 * 512 = 512 bytes

Sector size (logical/physical): 512 bytes / 512 bytes

I/O size (minimum/optimal): 512 bytes / 512 bytes

Disk /dev/loop7: 112.58 MiB, 118050816 bytes, 230568 sectors

Units: sectors of 1 * 512 = 512 bytes

Sector size (logical/physical): 512 bytes / 512 bytes

I/O size (minimum/optimal): 512 bytes / 512 bytes

Disk /dev/nvme0n1: 931.51 GiB, 1000204886016 bytes, 1953525168 sectors

Disk model: CT1000P3PSSD8

Units: sectors of 1 * 512 = 512 bytes

Sector size (logical/physical): 512 bytes / 512 bytes

I/O size (minimum/optimal): 512 bytes / 512 bytes

Disklabel type: gpt

Disk identifier: A623E266-750F-41B5-A008-9D469D3B85C3

Device           Start        End    Sectors   Size Type

/dev/nvme0n1p1    2048    2203647    2201600     1G EFI System

/dev/nvme0n1p2 2203648 1953521663 1951318016 930.5G Linux filesystem

Disk /dev/sda: 14.55 GiB, 15623782400 bytes, 30515200 sectors

Disk model: USB Flash Disk

Units: sectors of 1 * 512 = 512 bytes

Sector size (logical/physical): 512 bytes / 512 bytes

I/O size (minimum/optimal): 512 bytes / 512 bytes

Disklabel type: gpt

Disk identifier: 7CD178B0-860E-4729-A4A3-CD7BAE592982

Device        Start      End  Sectors  Size Type

/dev/sda1        64 12988431 12988368  6.2G Microsoft basic data

/dev/sda2  12988432 12998591    10160    5M EFI System

/dev/sda3  12998592 12999191      600  300K Microsoft basic data

/dev/sda4  13000704 30513151 17512448  8.4G Linux filesystem

Disk /dev/loop8: 531.38 MiB, 557187072 bytes, 1088256 sectors

Units: sectors of 1 * 512 = 512 bytes

Sector size (logical/physical): 512 bytes / 512 bytes

I/O size (minimum/optimal): 512 bytes / 512 bytes

Disk /dev/loop9: 18.49 MiB, 19386368 bytes, 37864 sectors

Units: sectors of 1 * 512 = 512 bytes

Sector size (logical/physical): 512 bytes / 512 bytes

I/O size (minimum/optimal): 512 bytes / 512 bytes

Disk /dev/loop10: 48.09 MiB, 50421760 bytes, 98480 sectors

Units: sectors of 1 * 512 = 512 bytes

Sector size (logical/physical): 512 bytes / 512 bytes

I/O size (minimum/optimal): 512 bytes / 512 bytes

Disk /dev/loop12: 10.83 MiB, 11354112 bytes, 22176 sectors

Units: sectors of 1 * 512 = 512 bytes

Sector size (logical/physical): 512 bytes / 512 bytes

I/O size (minimum/optimal): 512 bytes / 512 bytes

Disk /dev/loop11: 91.69 MiB, 96141312 bytes, 187776 sectors

Units: sectors of 1 * 512 = 512 bytes

Sector size (logical/physical): 512 bytes / 512 bytes

I/O size (minimum/optimal): 512 bytes / 512 bytes

Disk /dev/loop13: 576 KiB, 589824 bytes, 1152 sectors

Units: sectors of 1 * 512 = 512 bytes

Sector size (logical/physical): 512 bytes / 512 bytes

I/O size (minimum/optimal): 512 bytes / 512 bytes

raxtt · February 24, 2026, 1:51am

When I got to

sudo update-grub

I got this error

/usr/sbin/grub-probe: error: failed to get canonical path of '/cow'.

rubi1200 · February 24, 2026, 5:38am

Welcome to Ubuntu Discourse

That error means you’re trying to install GRUB to the temporary LiveUSB memory instead of your hard drive.

Because the LiveUSB uses a virtual filesystem called Copy-On-Write (/cow), GRUB gets confused.

You need to chroot into your actual Linux installation from the live terminal so that the command targets your physical disk.

Please follow the exact instructions below from the liveUSB terminal environment.

Boot the computer with the Ubuntu liveUSB and choose to Try Ubuntu (very important)

Open a terminal in the live environment with Ctrl+Alt+T

Mount the main partition and EFI partition

sudo mount /dev/nvme0n1p2 /mnt
sudo mount /dev/nvme0n1p1 /mnt/boot/efi

Bind the virtual filesystems

for i in /dev /dev/pts /proc /sys /run; do sudo mount -B $i /mnt$i; done

chroot into the target system

sudo chroot /mnt

The terminal prompt will now show # instead of the usual $, which is the sign you are now inside your partitions

Reinstall and update GRUB

grub-install /dev/nvme0n1
update-grub

Assuming there are no errors from the previous commands, you can now exit the chroot (there might be warnings but you can ignore those and continue)

exit
sudo reboot

Fingers crossed and let us know what happens.

oldfred · February 24, 2026, 1:56pm

Boot-Repair did a full grub install as Rubi has suggested manually doing with chroot.

But it shows this error:

Locked-NVram detected.

What brand/model system? Some have extra UEFI secuirty setting to prevent USB boot and/or adding boot entries. Check UEFI settings.

Lenovo has this UEFI lock setting setting, others may be similar:
https://www.reddit.com/media?url=https%3A%2F%2Fi.redd.it%2Foygxuo193ui41.jpg